Frequently Asked Questions

Why is calibration needed in a civil lab?

To ensure that instruments (e.g., compression machines, balances, sieves) produce accurate results, which is critical for structural safety and compliance with engineering specifications.

What instruments require calibration?

Common equipment includes concrete compression machines, tensile testing machines, lab balances, ovens, thermometers, pressure gauges, sieves, and soil Proctor compaction equipment.

What is the difference between calibration and adjustment?

Calibration is the comparison of a device against a standard to check accuracy. Adjustment (or calibration adjustment) is the modification of the instrument to bring it within specification.

What is “as found/as left” data?

It provides data on the instrument’s accuracy before (as found) and after (as left) adjustment. This is crucial for evaluating if previous test results were accurate.

How often should equipment be calibrated?

It depends on usage, manufacturer recommendations, and criticality. However, most labs calibrate key instruments annually (e.g., concrete machines, scales), while some require more frequent checks, such as monthly or quarterly.

What if an instrument fails calibration?

It must be taken out of service, repaired, or adjusted. If it cannot be fixed, it must be replaced.

Can I specify points for my calibration?

Yes, you can specify particular points within the equipment’s range, though this might be considered a “limited calibration” if not covering the full operating range.

What environmental conditions are required?

Calibration should occur in a stable environment. For example, temperature should ideally be 20°C ± 2°C, and humidity controlled to prevent material expansion or contraction in sensitive instruments.